1. An organism that lives in and derives its nourishment from organic matter in stagnant or foul water.
2. An organism that derives its nourishment from nonliving or decaying organic matter.

1. Any organism that lives off dead or decaying organic material.
2. An organism that obtains its nutrients from non-living organic matter, usually dead and decaying plant or animal matter, by absorbing soluble organic compounds.

Since saprotrophs cannot make food for themselves, they are considered a type of heterotroph.

The term heterotroph, which is used in the definition above, refers to an organism that is unable to synthesize nutrients from inorganic compounds and therefore is dependent on complex organic molecules from external sources for growth.

The terms saprophyte, saprobe, and saprozoite denote saprotrophic plants, microbes and fungi, and animals respectively; but the boundaries are blurred in actual usage, with saprophyte being more widespread and traditional than the others.